Now that we have beaten the "Me262 earlier" to death, let's take this in another direction that actually might work. What if Hitler el. al. calls for a jet Volksjäger say in February 1944 after the US unleashes their "Big Week" campaign and P-51s are now appearing over Berlin. Let's assume that he and the higher ups in the Nazi political system are sufficently alarmed that they call for a mass produced non-strategic jet fighter to protect the Reich. Certainly the airframe design could have been produced by April or May 1944. Engines were available. The Jumo 004 and BMW 003 are both available in at least limited numbers at this point. Let's assume that since the 004 is already being put into the Me 262 and Ar 234 that the BMW 003 is specified. This could easily result in Henkel presenting the 162 and it being accepted for production in say May or June 44. Given the disasters of D-Day and the following breakout along with Bagration in the East I could see an earlier He 162 being in production by August 1944 and in service by October or November of that year. While such a development would not make a huge difference on the ground or in the overall outcome of the war, it certainly would have had an impact to have several hundred He 162 take on a US bomber formation. Unlike the cumbersome and heavy Me 262 the He 162 could have flown rings around any piston engined fighter of the period (assuming it doesn't come unglued...literally in flight). Given that the BMW 003 had a service life of about 100 hours or, about ten times that of the Jumo design both airplane and engine are matched to make them almost disposable as a unit. The Henkel also only takes about 1/3 the fuel of the Messerschmitt making it possible that a large number could have been flown at once. On the whole, the Henkel in service just 6 months earlier could have handed the Allies a shock for a time that the Me 262 never could.